feat(aws): add partition tag

[seungleelee]

What does this PR do?

Adds a aws.partition tag onto AWS traces based on the region. The logic to derive this partition is identical to what we do within the SQS arn extraction logic we added earlier.

Motivation

Part of a larger effort to better link cloud resources within Datadog. We often need the AWS partition during downstream enrichment - it is almost always a required part of constructing an ARN, but it's currently not captured in the library

Jira Ticket and more context around this effort

Reviewer's Checklist

• Changed code has unit tests for its functionality at or near 100% coverage.
• System-Tests covering this feature have been added and enabled with the va.b.c-dev version tag.
• There is a benchmark for any new code, or changes to existing code.
• If this interacts with the agent in a new way, a system test has been added.
• New code is free of linting errors. You can check this by running ./scripts/lint.sh locally.
• Add an appropriate team label so this PR gets put in the right place for the release notes.
• Non-trivial go.mod changes, e.g. adding new modules, are reviewed by @DataDog/dd-trace-go-guild.

Unsure? Have a question? Request a review!

[pr-commenter]

Benchmarks

Benchmark execution time: 2025-09-24 15:08:21

Comparing candidate commit fe92c5f in PR branch seunglee/CLP-1021 with baseline commit e2c8d45 in branch main.

Found 0 performance improvements and 0 performance regressions! Performance is the same for 24 metrics, 0 unstable metrics.

[darccio]

LGTM

[seungleelee]

/merge

[dd-devflow-routing-codex]

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2025-09-25 19:58:28 UTC ℹ️ Start processing command /merge

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2025-09-25 19:58:33 UTC ℹ️ MergeQueue: pull request added to the queue

The expected merge time in main is approximately 17m (p90).

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2025-09-25 20:11:26 UTC ℹ️ MergeQueue: This merge request was merged